Apparatus and method for routing a dedicated number through alternate telephone carriers

ABSTRACT

An apparatus and method are provided for routing a call to dedicated number through an AIN-based network. A predetermined sequence of preferred or ranked carriers is assigned to an end office from which a call originates. Input of the dedicated number at an end office number triggers the network to assign a primary carrier to connect the call based on a user selection, a Primary Interexchanged Carrier, or the first carrier indicated by the predetermined sequence. An alternate and secondary carrier may also be assigned based upon the predetermined sequence. The call is routed sequentially to the primary, alternate, and secondary carrier until a connection is established or until all routes are exhausted. The features of the invention are particular useful for routing calls to the Government Emergency Telecommunications Service (GETS).

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to the field oftelecommunications and to an apparatus and method for managingtelephony-based services, such as routing and translations services.More particularly, the present invention relates to an intelligent oradvanced application, such as an Advanced Intelligent Network (AIN)application, for routing a special or dedicated telephone number throughmultiple paths out of an AIN end office to a dedicated or specialpurpose telecommunications system, such as the Government EmergencyTelecommunications Service (GETS).

2. Acronyms

The written description provided herein contains acronyms which refer tovarious communication services and system components. Although known,use of several of these acronyms is not strictly standardized in theart. For purposes of the written description herein, acronyms will bedefined as follows:

10D--10 Digit Trigger

AIN--Advanced Intelligent Network

ACR--Alternate Carrier Routing

CCIS--Common Channel Interoffice Signaling

CCS--Common Channel Signaling

CO--Central Office

CIC--Carrier Identification Code

CPR--Call Processing Record

CPN--Calling Party Number

DID--Direct Inward Dialing

DLN--Dialed Line Number

DRS--Data and Reports System

EO--End Office

FIM--Feature Interaction Manager

ISCP--Integrated Service Control Point

ISUP--ISDN User Part

IXC--Interexchange Carrier

LATA--Local Access and Transport Area

MF--Multi-Frequency

NANP--North American Numbering Plan

NPA--Numbering Plan Area

NXX--Central Office Code

PIC--Primary Interexchange Carrier

PRI--Primary Rate Interface

PSTN--Public Switched Telephone Network

SCE--Service Creation Environment

SCP--Service Control Point

SMS--Service Management System

SRAS--Special Routing Access Service

SS7--Signaling System 7

SSP--Service Switching Point

STP--Signaling Transfer Point

TAT--Termination Attempt Trigger

TCAP--Transaction Capabilities Applications Part

TG--Trunk Group

TN--Telephone Number

3. Background Information

(a) Government Emergency Telecommunications Service (GETS)

GETS is a telecommunications system maintained by GTE and the federalgovernment for use during emergencies. Specifically, the Numbering PlanArea (NPA) code of 710 was established for the special federalgovernment telephone number 710-NCS-GETS (i.e., 710-627-4387). In theprior art, this telephone number was routed to GETS either through thePrimary Interexchange Carrier (PIC) of the calling location for officeswith a GETS service, or through AT&T for a calling location that hascontracted with AT&T for Special Routing Access Service (SRAS).

A drawback of the above arrangement is that only a single telephonecarrier is available for connecting any one node/office to GETS.However, during an emergency, the particular carrier may not beavailable and/or accessible. For example, a flood of calls to a disasterarea, downed communication lines, or damage to the carrier itself maycause service outage or overload.

(b) Advanced Intelligent Networks

In recent years, Advanced Intelligent Networks (AIN) have provided anumber of new telephone service features. The AIN evolved out of a needto increase the capabilities of the telephone network architecture tomeet the growing needs of telephone customers or users. The AINarchitecture generally comprises two networks, a data messaging networkand a trunked communications network. The trunked communications networkhandles voice and data communications between dispersed networklocations, whereas the data messaging network is provided forcontrolling operations of the trunked communications network.

An illustration of the basic components of AIN architecture is shown inFIG. 1. As shown in FIG. 1, Service Switching Points (SSP's) 64, 66, 68,and 70 are provided for sending and receiving data messages from aService Control Point (SCP) 56 via Signaling Transfer Points (STP's) 58,60, and 62. The data messages are communicated to and from the SSP's 64,66, 68, and 70 and the SCP 56 along a Common Channel Signaling (CCS)network 88. Each SSP 64, 66, 68, and 70 routes telephone calls between aplurality of dispersed network stations 172, 174, 176, 178, 180, 182,184, 186. For example, SSP's 64, 66, 68, and 70 may route a telephonecall between a calling station (e.g., station 172) and a called station(e.g., station 184) through trunks 90 and customer lines 92 (e.g.,telephone lines). Stations 172, 174, 176, 178, 180, 182, 184, 186 maycomprise various customer or terminal equipment, such as a telephoneunit (wired, cellular or mobile), a facsimile machine, and/or a modemattached to a personal computer.

More information regarding AIN may be found in various publications.See, for example, Berman, Roger K., and Brewster, John H., "Perspectiveson the AIN Architecture," IEEE Communications Magazine, February 1992,pp. 27-32, the disclosure of which is expressly incorporated herein byreference in its entirety.

A number of services or features provided by prior AIN or AIN-typeintelligent networks relate to specialized call processing or recordingof incoming calls and call traffic. For example, U.S. Pat. No. 5,583,926discloses routing of calls to dedicated numbers. The subscriber canselect an overflow routing option to provide a list of overflow routesor trunks to provide alternate routes within a single network to connecta call. The alternate routes may be available to the PrimaryInterexchange Carrier if the most direct route is overloaded.

A drawback of the above-noted patent is that while it establishesseveral routes to place calls to a carrier, it cannot route the call toan alternate carrier if the carrier is disabled or otherwiseinaccessible. Further, prior systems do not permit a user or party todial a dedicated number to optionally select a specific carrier and/orbackup carriers to ensure completion of the call.

OBJECTS OF THE PRESENT INVENTION

In view of the above, the present invention, through one or more of itsvarious aspects and/or embodiments is thus presented to accomplish oneor more objects and advantages, such as those noted below.

A general object of the invention is to provide an improved routingscheme for GETS calls that will increase the probability that a GETScall will be successfully completed. Such a routing scheme may includean apparatus and method for automatic routing of GETS calls.

Another object of the present invention is to provide an apparatus andmethod for sequentially routing a call to GETS to more than oneInterexchange Carriers (IXC's) to ensure that an alternate or secondaryalternate ("secondary") carrier can be used to complete the call if thenode/office cannot connect to the primary carrier. The ability to switchto other carriers increases the probability that the emergency call willconnect with an Interexchange Carrier to complete the call.

It is a further object of the invention to incorporate the above into anAIN environment, such that the SCP of the AIN performs a GETS AlternateCarrier Routing (GETS ACR) logic to assign primary, alternate, andsecondary carriers.

It is a still further object of the invention to monitor and classifythe GETS call for later retrieval for billing and/or statisticalanalysis.

SUMMARY OF THE PRESENT INVENTION

Accordingly, one aspect of the present invention is to assign defaultprimary, alternate, and secondary carriers to individual end offices ofthe AIN. These carriers are preferably selected from an interexchangecarrier group of telecommunications carriers, such as AT&T, MCI, andSprint. If the AIN end office cannot connect with the interexchangecarrier of a designated primary carrier, then the call will be routed tothe interexchange carrier of an alternate carrier. If the AIN end officefails to connect with the alternate carrier, then the system will routethe call through the interexchange carrier of a secondary carrier.

According to another aspect of the present invention, a caller canmanually select a primary carrier when placing a GETS call. Ifrequested, the system will assign alternate and secondary carriers basedon the highest rank of the carriers remaining in the assigned officedefault carriers. If the AIN end office fails to route the call to theselected primary carrier, then it can route the call through thealternate or secondary carriers.

According to yet another embodiment of the invention, the system assignsvalues to each of the selected modes of calls for statistical andbilling purposes.

According to an embodiment of the present invention, there is provided amethod for routing a call based on a dialed number from a location toone of a plurality of interexchange carriers. The location has apredetermined sequence of ranked preferred Interexchange Carriers. Themethod comprises selecting one of a specific carrier and a defaultcarrier, setting a primary carrier as the specific carrier when thespecific carrier is selected, and to one of an authorized PrimaryInterexchange Carrier and a first ranked carrier of the predeterminedsequence of ranked preferred carriers for the location when the defaultcarrier is selected, selecting at least one alternate carriersequentially from a highest remaining ranked carrier in thepredetermined sequence of ranked preferred carriers, and sequentiallyrouting the dialed number to the primary carrier and the at least onealternate carrier until a connection is established.

According to a feature of the above embodiment, the primary carrier isset to the first ranked carrier when the default carrier is requestedand the Primary Interexchange Carrier is not an authorized carrier.

According to a further feature of the above embodiment, the methodfurther includes providing at least one of a service code and a pegcount code based upon at least one of the dialed number, thepredetermined sequence of ranked preferred interexchange carriers, and asequence formed by the primary carrier and the at least one alternatecarrier.

According to a still further feature of the above embodiment, the methodincludes recording the at least one of the service code and the pegcount code for later retrieval and statistical analysis.

According to a still further feature of the above embodiment, therecording includes recording data regarding the dialed number, the dataincluding at least one of call time, call date, originating number,originating city, originating state, call duration, call disposition, aninterexchange carrier selection sequence, trunk group used, dialeddigits and destination number.

According to a still further feature of the above embodiment, the methodincludes recording the codes for later retrieval and billing.

According to a still further feature of the above embodiment, the methodincludes selectively overriding the calling party number with adedicated number.

According to a still further feature of the above embodiment, theselecting and sequentially routing are not performed if the specificcarrier is not an authorized carrier.

According to a still further feature of the invention, the selectingincludes entering a prefix code with the dialed number.

According to a still further feature of the invention, the methodfurther includes storing the predetermined sequence of ranked preferredcarriers in a look up table, and consulting the look up table to locatethe highest and next highest remaining ranked carrier.

According to another embodiment of the invention, there is provided amethod for routing a government emergency call from one of a pluralityof locations through one of a plurality of carriers. Each of theplurality of locations has predetermined ranking of preferredinterexchange carriers. The method comprises recognizing the call at onelocation of the plurality of locations, setting a primary carrier, inorder of preference, to one of an authorized manually selected carrierif entered, an authorized Primary Interexchange Carrier, and a firstranked carrier of the predetermined ranking of preferred carriers forthe one of the plurality of locations, selecting an alternate andsecondary carrier sequentially from a highest and next highest remainingcarrier in the predetermined ranking of preferred carriers for the onelocation, respectively, and sequentially routing the call tointerexchange carriers corresponding to the primary carrier, andalternate and secondary carriers when selected, until a connection isestablished.

According to a feature of the above embodiment, the method includesdisconnecting a user if a code for an unauthorized carrier is requestedby a user when dialing the call.

According to a further feature of the invention, each predeterminedranking of preferred carriers for each of the plurality of locationsincludes, in order of preference, the first carrier, and second andthird carriers, wherein if a user does not manually select a carrier andthe primary interexchange carrier is unauthorized, then the primary,alternate and secondary carriers are set to the first, second and thirdcarriers for the one location.

According to a still further feature of the invention, eachpredetermined ranking of preferred interexchange carriers for theplurality of locations includes three carriers.

According to a still further feature of the invention, the method alsoincludes recording data associated with the call, including at least oneof a call time, a call date, an originating number, an originating city,an originating state, a call duration, a call disposition, aninterexchange carrier, an interexchange carrier selection sequence, atrunk group used, dialed digits, and a destination number.

According to yet another embodiment of the invention, there is provideda network capable of routing a dedicated number through a plurality ofinterexchange carriers upon entry of the dedicated number and a requestcode. The network includes a device for dialing the dedicated number andthe request code, a node connected to the device, and a central controlconnected to the node. The node has a predetermined sequence of threepreferred carriers assigned to it.

The node requests carrier data from the central control responsive toentry of the dedicated number. The central control, responsive to afirst condition of the request code, sets a primary carrier to one ofthe three carriers which has a carrier identification code that matchesa predetermined portion of the request code. The central control,responsive to a second condition of the request code, disconnects thecall. The central control, responsive to a third condition of therequest code, sets a primary carrier to a Primary Interexchange Carrierfor the node if the Primary Interexchange Carrier is authorized, and toa first ranked carrier of the three preferred carriers if the PrimaryInterexchange Carrier is not authorized. The central control, responsiveto a fourth condition of the request code, sets an alternate carrier toa highest remaining rank carrier of the three carriers, and sets asecondary carrier to a next highest remaining rank carriers of the threecarriers. The central control replies to the node with the carrier data,including at least the primary carrier, and the alternate and secondarycarriers when set. The node routes the dedicated number to aninterexchange carrier corresponding to the primary carrier. The node,responsive to a selection of alternate and secondary carriers by thecentral control and a failure of the node to connect with theinterexchange carrier corresponding to the primary carrier, sequentiallyroutes the dedicated number to an interexchange carrier corresponding tothe alternate and secondary carriers until a connection is established.

According to a feature of the above embodiment, the network is anAdvanced Intelligent Network, the node is an end office, and the centralcontrol is a service control point.

According to a further feature of the above embodiment, the firstcondition is entry of a code which request a specific authorizedcarrier, the second condition is entry of a code which does notcorrespond to an authorized carrier, the third condition is entry of acode which does not request a specific carrier, and the fourth conditionis entry of a code which requests assignment of alternate and secondarycarriers.

According to a still further feature of the above embodiment, thecentral control further provides classification data based on at leastone of the requested code and the carrier data, wherein theclassification data may be retrieved for at least one of statisticalanalysis and billing.

According to a still further feature of the above embodiment, the systemalso includes a mechanism which selectively changes a calling partynumber to match the dedicated number.

According to yet another embodiment of the invention, there is provideda system for improving the probability that calling a dedicated numberwill connect through a node to one of a plurality of interexchangecarriers. The node has a predetermined sequence of preferred carriersassigned thereto. A mechanism recognizes the dedicated number. Amechanism assigns primary, alternate and secondary carriers responsiveto the recognizing mechanism. A mechanism sequentially routes thededicated number from the node to the interexchange carriercorresponding to the primary, alternate, and secondary carriers until aconnection is established.

According to a feature of the above embodiment, the system also includesa mechanism that assigns classification data based on at least one of acode input with the dedicated number and the assigned primary,alternate, and secondary carriers. The classification data is used forat least one of statistical analysis and billing.

According to a still further feature of the above embodiment, the systemis an advanced intelligent network, the node is an end office of thenetwork, and the dedicated number is entered at a device connected tothe end office.

According to yet another embodiment of the invention, there is provideda method for routing a call based on a dialed number from a location toone of a plurality of interexchange carriers, the location having apredetermined sequence of ranked preferred interexchange carriers. Themethod comprises, setting a primary carrier at one of an authorizedPrimary Interexchange Carrier and a first ranked carrier of thepredetermined sequence of ranked preferred carriers for the location,selecting at least one alternate carrier sequentially from a highestremaining ranked carrier in the predetermined sequence of rankedpreferred carriers, and sequentially routing the dialed number to theprimary carrier and the at least one alternate carrier until aconnection is established.

According to a feature of the above embodiment, the primary carrier isset to the first ranked carrier when the Primary Interexchange Carrieris not an authorized carrier.

According to further feature of the above embodiment, further comprisingproviding at least one of a service code and a peg count code based uponat least one of the dialed number, the predetermined sequence of rankedpreferred interexchange carriers, and a sequence formed by the primarycarrier and the at least one alternate carrier.

According to a still further feature of the above embodiment, the methodfurther comprises recording the at least one of the service code and thepeg count code for later retrieval and statistical analysis.

According to a still further feature of the above embodiment, therecording includes recording data regarding the dialed number, the dataincluding at least one of call time, call date, originating number,originating city, originating state, call duration, call disposition, aninterexchange carrier, an interexchange carrier selection sequence,trunk group used, dialed digits and destination number.

According to yet another feature of the above embodiment, the methodfurther comprises recording the codes for later retrieval and billing.

According to a still further feature of the above embodiment, thelocation has a calling party number, and the method selectivelyoverrides the calling party number with a dedicated number.

According to a still further feature of the above embodiment, the methodfurther comprises storing the predetermined sequence of ranked preferredcarriers in a look up table, and consulting the look up table to locatethe highest remaining ranked carrier.

According to yet another embodiment of the invention, there is provideda method for routing a call from one of a plurality of locations throughone of a plurality of carriers, each of the plurality of locationshaving a predetermined ranking of preferred interexchange carriers. Themethod comprises recognizing the call at one location of the pluralityof locations, setting a primary carrier, in order of preference, to oneof an authorized manually selected carrier if entered, an authorizedPrimary Interexchange Carrier, and a first ranked carrier of thepredetermined ranking of preferred carriers for the one location,selecting, when the authorized manually selected carrier is not entered,an alternate and secondary carrier sequentially from a highest and nexthighest remaining carrier in the predetermined ranking of preferredcarriers for the one location, respectively, and sequentially routingthe call to interexchange carriers corresponding to the primary carrier,and the alternate, and secondary carriers when selected, until aconnection is established.

According to a feature of the above embodiment, the method furthercomprises disconnecting a user if a code for an unauthorizedinterexchange carrier is requested by a user when dialing the call.

According to a further feature of the above embodiment, eachpredetermined ranking of preferred carriers for each of the plurality oflocations includes, in order of preference, the first carrier, andsecond and third carriers. If a user does not manually select a carrierand the primary interexchange carrier is unauthorized, then the primary,alternate and secondary carriers are set to the first, second and thirdcarriers for the one location.

According to a still further feature of the above embodiment, eachpredetermined ranking of preferred carriers for the plurality oflocations includes three interexchange carriers.

According to yet another feature of the above embodiment, the methodfurther comprises recording data associated with the call, including atleast one of a call time, a call date, an originating number, anoriginating city, an originating state, a call duration, a calldisposition, an interexchange carrier, an interexchange carrierselection sequence, a trunk group used, dialed digits, and a destinationnumber.

According to still another embodiment of the invention, there isprovided a network capable of routing a dedicated number through aplurality of interexchange carriers upon entry of the dedicated numberand a request code. The network includes a device for dialing thededicated number and the request code. A node is connected to thedevice. A central control is connected to the node. The node has apredetermined sequence of preferred carriers. The node requests carrierdata from the central control responsive to entry of the dedicatednumber. The central control, responsive to a first condition of therequest code, sets a primary carrier to one of the predeterminedsequence of preferred carriers which has a carrier identification codethat matches a predetermined portion of the request code. The centralcontrol, responsive to a second condition of the request code,disconnects the call. The central control, responsive to a thirdcondition of the request code, sets the primary carrier to a PrimaryInterexchange Carrier for the node if the Primary Interexchange Carrieris authorized, and to a first ranked carrier of the predeterminedsequence of preferred carriers if the Primary Interexchange Carrier isnot authorized. The central control, responsive to the third conditionof the request code, sets an alternate carrier to a highest remainingrank carrier of the predetermined sequence of preferred carriers, andsets a secondary carrier to a next highest remaining rank carriers ofthe preferred carriers. The central control replies to the node with thecarrier data, including at least the primary carrier, and the alternateand secondary carriers when set. The node routes the dedicated number toan interexchange carrier corresponding to the primary carrier. The node,responsive to a selection of alternate and secondary carriers by thecentral control and a failure of the node to connect with theinterexchange carrier corresponding to the primary carrier, sequentiallyroutes the dedicated number to an interexchange carrier corresponding tothe alternate and secondary carriers until a connection established.

According to a feature of the above embodiment, the network is anAdvanced Intelligent Network, the node is an end office, and the centralcontrol is a service control point.

According to a further feature of the above embodiment, the firstcondition is entry of a code which requests a specific authorizedcarrier, the second condition is entry of a code which does notcorrespond to an authorized interexchange carrier, and the thirdcondition is entry of a code which does not request a specific carrier.

According to a still further feature of the above embodiment, thecentral control provides classification data based on at least one ofthe requested code and the carrier data. The classification data may beretrieved for at least one of statistical analysis and billing.

According to a still further feature of the above embodiment, thededicated number is entered at a location having a calling party number.The system further includes a mechanism which selectively changes thecalling party number to match the dedicated number.

The above-listed and other objects, features and advantages of thepresent invention will be more fully set forth hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is further described in the detailed descriptionthat follows, by reference to the noted plurality of drawings by way ofnon-limiting examples of preferred embodiments of the present invention,in which like references numerals represent similar parts throughout theseveral views of the drawings, and wherein:

FIG. 1 illustrates an exemplary block diagram of the basic components ofa conventional, Advanced Intelligent Network (AIN) system.

FIG. 2 illustrates, in a general block diagram form, an AdvancedIntelligent Network (AIN) based system for implementing automaticrouting features, in accordance with an embodiment of the presentinvention;

FIG. 3 illustrates the basic schematic of the present invention in anAIN system;

FIG. 4 illustrates a flow chart of the service logic to select carrierswhen a user places a call to GETS;

FIG. 5 illustrates a flow chart of the service logic to route the callafter the carriers are selected;

FIG. 6 illustrates, in accordance with another aspect of the invention,a flow chart of the service logic after the carriers are selected tooverride a calling party number; and

FIG. 7 illustrates a flow chart of the service logic to select carrierswhen a user places a call to GETS according to a second embodiment ofthe invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A. AIN ENVIRONMENT

Many telephone services may be provided using an AIN or AIN-type networkarrangement for centralized control of telephone services offered tocustomers, as opposed to localized control of services at the CentralOffice (CO) or End Office (EO). An AIN system may be provided throughinteraction between switching points and other systems supporting AINlogic.

According to an aspect of the present invention, an apparatus and methodfor routing GETS calls may be implemented using an AIN or AIN-typenetwork. In particular, an AIN network with at least AIN Release 0.0 orAIN Release 0.1 protocols and advanced intelligent network capabilitiesmay be utilized to implement the various features and aspects of theinvention. It should be noted, however, that the implementation of thepresent invention is not limited to AIN-based networks. Similarly, otheradvanced or intelligent networks and arrangements, other than theexemplary AIN system disclosed herein, may be used to implement theinvention.

Referring now to the accompanying drawings, FIG. 2 illustrates anAIN-based network arrangement for implementing the invention. In theembodiment of FIG. 2, a telephone network within LATA 61 is providedthat defines a calling service area. The LATA 61 includes stations,e.g., stations 13A, 13B, 14A, 14B, 15A, 15B, 16A, 16B, 17A and 17B, andcorresponding switches, e.g., service switching points (SSP) or endoffices (EO) 13, 14, 15, 16 and 17. The EO's 13, 14, 15, 16 and 17 maycomprise, for example, 1AESS or 5ESS switches manufactured by, forexample, Lucent Technologies, Inc., having AIN Release 0.1 capabilitiesand protocols, DMS-100 switches manufactured by, for example, Nortelhaving AIN Release 0.1 capabilities and protocols, AXE-10 switchesmanufactured by, for example, Ericsson having AIN Release 0.1capabilities and protocols, or 1AESS switches, additionally having AINRelease 0.0 capabilities and protocols. Additionally, having AIN Release0.0 capabilities and protocols may be possible for the DMS-100 and 5ESSswitches. Further, in accordance with an aspect of the presentinvention, as new AIN Releases and protocols (e.g., AIN Release 0.2) areintroduced, the capabilities of the SSP's and the service logic of thepresent invention may be upgraded accordingly.

As presently contemplated, routing of GETS calls is applicable tooffices having the 5ESS, DMS-100, and 1AESS switches with AIN Release0.1 capabilities and protocols, and to a lesser extent through 1AESSswitches with AIN release 0.0 protocols. Additionally, it may bepossible to utilize the system with other switches noted above,including upgrades as issued.

In the example shown in FIG. 2, each switch may include different typesof facilities and/or triggers. Generally, SSP's 13-17 are eachprogrammable switches which: recognize AIN-type calls; launch queries toservice control point (SCP) 101; and, receive commands and data from SCP101 to further process and route AIN-type calls. When one of the SSP'sis triggered by an AIN-type call, the triggered SSP formulates an AINservice request and responds to call processing instructions from thenetwork element in which the AIN service logic resides. According to anaspect of the invention, the AIN service logic may reside in a databaseat SCP 101.

As further shown in FIG. 2, either a direct route or a tandem route mayexist between all switches. In LATA 61, direct trunks 20 exist betweenSSP 13, SSP 14, SSP 15, SSP 16 and SSP 17. Assuming LATA 61 to be alarge service area, direct trunks may not be available between eachswitch, either due to geographical limitations or due to excessivetraffic. For example, SSP 13 may alternatively use tandem trunk 21 to atandem switch 31 and may use trunk 20 to SSP 17 to terminate an offeredcall. This alternative path may be an overflow route for traffic thatcannot find room on trunk 20 between SSP 13 and SSP 17. Trunks 21 may beeither SS7, controlled multi-frequency trunks (MF), or primary rateinterface (PRI) trunks, and the type of trunk will be in accordance withboth the sending and receiving SSP to which it is connected. If eitherof the SSP's is a 1AESS type switch, the trunk will either be an SS7 orcontrolled MF type trunk, as the 1AESS is not capable of supporting PRItrunks. However, if both the sending and receiving switches are either aDMS-100 switch or a 5ESS switch, the trunk may be either an SS7, acontrolled MF type trunk, or PRI type trunk.

Each office equipped as an AIN SSP may allow normal switch processing tobe suspended at specific points in a call so that the switch may send anAIN message query to SCP 101. Service control point 101 may executesoftware based service logic and return call processing instructions tothe triggering AIN SSP. In addition, SCP 101 may comprise an IntegratedService Control Point (ISCP). New services may be provisioned byassigning AIN SSP triggers to customer lines, trunks, and/or NANPtelephone numbers. As noted above, the SSP's may include, but are notlimited to, 5ESS, 1AESS, and DMS-100 switches. The 5ESS switches mayutilize an AIN Release 0.1 protocol and should be equipped with Generic5E9.1 (or higher) software and associated AIN SSP features in order toserve customers. The 1AESS switches may use an AIN Release 0.0 protocolor an AIN Release 0.1 protocol, and should be equipped with Generic1AE12.03 (or higher) software and associated AIN SSP features in orderto serve customers. The DMS switches may utilize an AIN Release 0.1protocol and should be equipped with Generic NA003 (or higher) softwareand associated AIN SSP features. Specifications of AIN Release 0.1 SSP'smay be found in Bellcore documents TR-NWT-001284, "Advanced IntelligentNetwork Release 0.1 Switching System Generic Requirements", Issue 1(August 1993), and TR-NWT-001285, "Advanced Intelligent Network 0.1Switch-Service Control Point Application Protocol Interface GenericRequirements", Issue 1 (August 1992) from Bell Communications Research,Inc., of Livingston, N.J., the disclosures of each document isincorporated by reference herein in its entirety.

As described above, within LATA 61 is a tandem switch 31 that isconnected to each of the SSP's 13-17. The tandem switch 31 is coupled toeach of the SSP's 13-17 of LATA 61 by trunks 21. Trunks 21 mayinterconnect tandem switch 31 with each SSP within LATA 61 for routingtelephone calls. However, trunks 21 may also be used to connect tandemswitch 31 to, e.g., toll calls that terminate on SSP's (not shown)outside LATA 61; and, calls originating outside of LATA 61 butterminating on an SSP within LATA 61.

As noted above, the SCP 101 may comprise an Integrated Service ControlPoint (ISCP). The ISCP (not shown) is an integrated system which mayinclude a service management system (SMS), a data and reports system(DRS), a programmable service control point (SCP), and a servicecreation environment (SCE). The SCE may be provisioned as a terminalimplemented to work with SMS to create, modify, and load services intothe SCP database. The SCE may comprise, for example, a programmingenvironment (such as the SPACE.SM. programming environment that isavailable from Bellcore) for creating and provisioning services. The SCPmay execute software-based service logic and return call routinginstructions to the triggering SSP's. The SMS may be provided foradministrative purposes to synchronize customer CPR and data on themated pair of ISCP's that SCP 101 represents. The DRS may be providedfor compiling call information to be used for billing and administrativepurposes. By way of example, the ISCP may be implemented with a BellcoreIntegrated Service Control Point (ISCP), loaded with preferably at leastISCP software Version 4.0 (or higher), available from BellCommunications Research, Inc., of Livingston, N.J.

In order to facilitate signaling and data messaging, each SSP and tandemswitch within the multiple location AIN is equipped with Common ChannelSignaling (CCS) capabilities, e.g., Signaling System 7 (SS7), whichprovides two-way communications of data messages over CCS links 43, 44,45, 46, 47, 48, 73 and 91 between each SSP and tandem switch 31 and theSCP 101. The data messages may be formatted in accordance with theTransaction Capabilities Applications Part (TCAP). Alternatively, ISDNUser Part (ISUP) may be used for signaling purposes between, forexample, SSP's 13-17. In such a case, the SSP's may be equipped with thecapability to map appropriate data between TCAP and ISUP protocols, andvice versa. The telephone network essentially employs an upper-levelsoftware controlled network through the Signaling Transfer Points(STP's) and the SCP (and/or ISCP). The software presides over thehardware to check the call route and the availability of connectionprior to hardware connection.

Accordingly, the connections by links 43-48, link 73, and link 91through STP's 53 and 81 are for signaling purposes, and allow each ofthe SSP's 13-17 to send and receive messages to and from SCP 101 via theSTP's. As shown for example in FIG. 2, a local STP 53 may act as thedata messaging control point for LATA 61. That is, all data messagesfrom SSP's within LATA 61 or directed to SSP's within LATA 61 may betransmitted through STP 53. Accordingly, CCS links 43-48 are shownestablishing a data link between STP 53 and either the tandem switch 31,SSP 13, SSP 14, SSP 15, SSP 16 or SSP 17. Further, one or more regionalSTP's may be provided for data messaging with each of the LATA. In FIG.2, regional STP 81 is illustrated as receiving and transmitting datamessages with LATA 61 by connecting to STP 53 by line 73 and connectingto SCP 101 by link 91.

B. COMMUNICATIONS NETWORK TRIGGERS AND HARDWARE

1. AIN Triggers

The AIN may include at least three AIN triggers that may be implementedon the above-described AIN SSP's to facilitate accessing the routingfeatures for dedicated or GETS calls. The 5ESS, DMS-100, and 1AESS AINSSP's may be provisioned with a termination attempt trigger (TAT), and a10 digit trigger (10D). The 1AESS AIN SSP may be provisioned with adialed line number trigger (DLN), which is equivalent to the TAT.According to the present invention, other types of triggers may also bequickly and easily added.

The preferred trigger for use with the present invention is the 10 digittrigger. The 10 digit trigger is an office based trigger that may beassigned to a dialed number, and is associated with AIN Release 0.1.Accordingly, the 10 digit trigger may be programmed to recognize adedicated or designated telephone number and to trigger AINfunctionality in response to recognizing the designated telephonenumber.

On the 5ESS switch, a 10D trigger is preferable if there are more than,for example, 99 simultaneous trigger events expected per TN.

2. Service Control Point

The AIN herein may require several service logic programs (or callprocessing records (CPR)) to fully implement the subscriber's desiredservice features within a single network. Each CPR may be triggeredbased on calls initialed by or placed to the subscriber. The trigger CPRmay have one or more graphs to permit a subscriber's telephone number tobe compatible with different AIN releases. For example, each subscribermay have a TN associated with a trigger CPR having a trigger graph foran AIN Release 0.0 implementation of subscribed service, and a triggergraph for an AIN Release 0.1 implementation of the subscribed service.However, common service logic for both AIN releases may be in the sameCPR with protocol particular logic. The CPR may have a number ofassociated tables to be accessed by the SCP in implementing theparticular service logic. It is also noted that each terminating andoriginating station may have a trigger CPR, depending on the triggerimplemented by the provisioner. Generally, a trigger CPR may be smalland may include one or more graphs. Each graph within a trigger CPR mayinclude at least two nodes (i.e., branch points within the servicecreation logic). For example, the graph may contain interconnected nodesto provide the service creation logic. In addition, each trigger CPR mayinclude at least one call variable used by each graph to create theappropriate service logic. A graph may also use constants and callvariables in executing the service logic. In addition, the callvariables may be exclusive to a graph, shared among all graphs of a CPR,or shared among multiple CPR's. Call variables may be predefined fromSS7 queries or for use in SS7 responses. Predefined call variables aretypically related to messages (e.g., query, conversational, or response)between the SSP and the ISCP or ISCP and machine constants, such astime-of-day. A particular type of call variable may be an embeddedtable. Call variables may be service creator defined and may includesubscriber supplied data, or may be temporarily defined during theexecution of the service logic. Further, call variables may berestricted to the graph in which it is defined or to the CPR in which itis defined. A stand alone table is a unique object at the same level asa CPR. Embedded tables and stand alone tables are not a subset of CPR'sequivalent to graphs in the SCP.

At the SCP, a CPR that has been converted into an object is called atemplate. A template "freezes" the service logic and allows user definedcall variables to be reset to provisionable parameters that have labelfields in the template to assist the user in setting the value ofprovisionable parameters.

The service provisioner needs to know the AIN release or version of eachnetwork station's serving SSP because the SCP may use the telephonenumber and the AIN trigger type to generate a unique key or code foraccess to AIN functionality. Because AIN Release 0.1 and AIN Release 0.0are different, some aspects of a service may need to be separatedaccording to the AIN release. Further, to create a unique key for accessto AIN functionality, the AIN release may be needed to ensure that theproper service creation features and the protocols are utilized foreffective and accurate communication with the SSP.

According to the present invention, the trigger CPR may include separategraphs or service logic for each trigger (e.g., TAT, 10D and DLN), so asto support all trigger types within one set of subscriber provided datafor call variables. Separate CPR's or graphs may also be provided foreach of AIN Release 0.0 and Release 0.1 in order to improve performance;however, it is possible to use a single CPR to support the servicefeatures of the invention across AIN releases, as the individual tablesstored in the SCP may be designed to accommodate all AIN versions of thepresent service. Accordingly, the CPR may need to know what type of SSPis providing the AIN trigger and query message. The present inventionmay be adapted for use with terminating triggers or originatingtriggers. The terminating (or originating, if applicable) trigger CPRmay be designed to transfer control to an appropriate "transfer in"graph to translate the switch commands into common call variables usableby the CPR to continue the service logic. Use of the "transfer in" graphensure maximum software reuse but may decrease SCP performance(capacity). A major function of the "transfer in" graph is to transformdata in either AIN Release 0.0 or in AIN Release 0.1 protocol togeneric, protocol insensitive values that the common service logic CPRcan process. At the end of the common service logic CPR, control istransferred over to a "transfer out" graph to prepare an appropriateprotocol response to send back to the SSP. Optionally, rather thanemploying a "transfer in" graph, the predefined call variables from thequery and provisionable parameters may be used as is to transfercontrol.

When the triggering event, i.e., termination or origination of theoffered call, occurs, the SSP may send a query for that calling partynumber (CPN) to the SCP. The SCP may use the CPN for screening and/orbilling purposes as defined in the CPR.

C. GOVERNMENT EMERGENCY TELECOMMUNICATIONS SERVICE

Referring now to FIG. 3, an exemplary GETS ACR system of the presentinvention is shown generally at 1000. In FIG. 3, a telephone 1002, EndOffice (EO) 1004, STP 1006, SCP 1008 having an ISCP, and Access Tandem(AT) 1010, may be configured to the corresponding elements in the abovedescribed AIN system environment of FIG. 2. The preferred features ofthe invention will be described below with reference to the noted AINenvironment. However, the invention is not so limited, as the presentinvention may be used with non-AIN systems or AIN's having otherconfigurations.

As shown in FIG. 3, telephone 1002 connects to EO 1004, which may beconfigured as an SSP. EO 1004 communicates with SCP 1008 through STP1006 and CCS links, and routes or transfers calls to an Access Tandem1010 through a trunked line. Interexchange carriers (IXC's) 1012, 1014,and 1016, connect to AT 1010, STP 1006, and EO 1004.

When the GETS ACR system is installed for an EO 1004, that office isassigned by the GETS manager or administrator (currently GTE) apredetermined sequence or ranking of preferred carriers. For example,one office may be assigned AT&T as primary carrier, MCI as alternatecarrier, and Sprint as secondary carrier. In the preferred embodiment,these three carriers are used to fill the three carrier slots, providingsix possible permutations of primary, alternate, and secondary carriers.

To implement GETS ACR, the telephone number 710-NCS-GETS is assigned aten (10) digit trigger for EO 1004. Once the trigger is assigned andactivated, EO 1004 responds to every GETS ACR call to 710-NCS-GETS bysending an AIN query message to SCP 1008 through STP 1006 and the SS7network. SCP 1008 executes the GETS ACR logic to select at least aprimary carrier, as well as alternate and secondary carriers whenrequested.

The user can manually select a carrier or request automatic assignmentof carriers when placing the GETS call (710-NCS-GETS) by dialing aprefix code (e.g, 0, 1, or 10XYZ, where X, Y, and Z are any digitbetween 0 and 9). The following routing selections are contemplated forthe preferred embodiment:

(1) 10XYZ+1+GETS call: carrier with a carrier identification code (CIC)which corresponds to the XYZ code is selected as the primary carrier;alternate and secondary carriers are selected from the rank of theremaining assigned carriers.

(2) 10XYZ+0+GETS call: carrier with a CIC which corresponds to the XYZcode is selected as the primary carrier; no alternate and secondarycarriers are selected.

(3) 0+GETS call: MCI is selected as primary carrier; no alternate andsecondary carriers are selected.

(4) 1+GETS call: primary, alternate and secondary carriers are assignedautomatically based on the local PIC and the rank order of the remainingcarriers.

If an entered XYZ code does not correspond the CIC of anauthorized/recognized Interexchange Carrier (IXC), then the systemdisconnects the call.

A detailed flowchart of the program and operations by which theappropriate carriers are selected is shown in FIG. 4. At step S100, EO1004 recognizes the entry of the GETS call (i.e.,710-NCS-GETS) andexecutes the appropriate AIN trigger (such as a Dialed Number Trigger(DNT) or a 3/6/10 digit AIN trigger), and sends a query message to SCP1008. At step S102, SCP 1008 executes the GETS ACR logic based on thereceived query message to first determine whether the call was precededby a five digit code 10XYZ. If so, the service logic compares the XYZcode with the CIC's of the recognized carriers at step S104. Forexample, the presently utilized CIC's are 288 for AT&T, 222 for MCI, and333 for Sprint; accordingly, SCP 1008 will recognize 10288 as aselection of AT&T, 10222 and a selection of MCI, and 10333 as Sprint.

If the XYZ code does not correspond to the CIC of any recognizedcarrier, then control proceeds to step S114 for a peg count (in whichthe system issues a peg value code indicating that the caller dialed aninvalid code for later statistic analysis) of the call. The systemfinally disconnects the call after playing an error message at stepS116.

If the XYZ matches one of the recognized carriers, then the servicelogic sets the primary carrier to the carrier with the corresponding CICat step S106. The service logic then determines whether selection ofalternate and secondary carriers is necessary at step S108 based onwhether the 10XYZ+0+GETS call was dialed. If so, then no alternate orsecondary carriers are selected, and control proceeds to the executionsubroutine at step S132 (see FIG. 5).

If the 10XYZ code is not followed by a zero (i.e., 10XYZ+1+GETS call)then the service logic consults a lookup table in SCP 1008 at step S110for the assigned primary, alternate, and secondary carriers for the AINEO (e.g., EO 1004) which is the source of the GETS ACR call; thecarriers for each EO are preferably ranked according to a predeterminedor default list of interexchange carrier's stored in SCP 1008. At stepS112, the highest remaining ranked carrier (HRR) is assigned as thealterative carrier, while the next highest remaining ranked carrier(NHRR) is assigned as the secondary carrier. By way of example, supposethat a particular AIN office has assigned default carriers as follows:primary=AT&T (288); alternate=MCI (222); and secondary=Sprint (333). Ifa user inputs 10222+1+call, MCI is selected as the primary carrier, AT&Tas the alternate carrier (as the highest ranking remaining carrier), andSprint as the secondary (as the next highest remaining carrier).Similarly, if a user inputs 10333+1+call, Sprint is selected as theprimary carrier, AT&T as the alternate carrier (as the highest rankingremaining carrier), and MCI as the secondary (as the next highestremaining carrier).

With the alternate and secondary carriers now selected, control proceedsto the execution sequence at step S132 (discussed below with referenceto FIG. 5). Returning to step S102, if the user did not input a 10XYZprefix (i.e., only a 1 or 0 prefix was entered), then control proceedsto step S118 to determine whether a zero prefix was entered. If so, thenMCI is selected as the primary carrier without alternate or secondarycarriers by the SCP 1008 at step S120; control then proceeds to stepS132.

If the prefix is not zero, the service logic looks up the assigneddefault carriers at step S122. At step S124, the system determineswhether the Primary Interexchange Carrier (PIC) to which the callingstation is automatically connected is an authorized carrier (i.e., oneof the default carriers or other specifically designated carrier). Ifnot, then the primary, alternate, and secondary carriers are set at theoffice default settings at step S126, whereupon control proceeds to theexecution subroutine at step S132. If the PIC is an authorized carrier,then the primary carrier is set to the PIC at step S128, while thealternate and secondary carriers are selected as the highest and nexthighest remaining rank carriers, respectively, at step S130; controlthen proceeds to step S132 (see FIG. 5).

Based on the above service logic flows, various possible permutations ofdialed numbers and assigned carriers based on a three carrier systemusing, for example, AT&T, MCI, and Sprint are possible. Table 1 belowindicates the exemplary permutations of dialed numbers and assignedcarriers according to an aspect of the present invention.

                                      TABLE 1                                     __________________________________________________________________________                                          SECONDARY                               CALLER DIALS   PIC is:                                                                            PRIMARY CXR                                                                            ALTERNATE CXR                                                                          ALTERNATE CXR                           __________________________________________________________________________    1 + 710 + NCS + GETS                                                                         AT&T AT&T     Highest Remaining                                                                      Next Highest                                                         Ranked (HRR)                                                                           Remaining Ranked                                                              (NHRR)                                  1 + 710 + NCS + GETS                                                                         MCI  MCI      HRR      NHRR                                    1 + 710 + NCS + GETS                                                                         SPRINT                                                                             SPRINT   HRR      NHRR                                    1 + 710 + NCS + GETS                                                                         OTHER                                                                              OFFICE DEFAULT                                                                         OFFICE DEFAULT                                                                         OFFICE DEFAULT                          0 + 710 + NCS + GETS                                                                         AT&T MCI      NONE     NONE                                    0 + 710 + NCS + GETS                                                                         MCI  MCI      NONE     NONE                                    0 + 710 + NCS + GETS                                                                         SPRINT                                                                             MCI      NONE     NONE                                    0 + 710 + NCS + GETS                                                                         OTHER                                                                              MCI      NONE     NONE                                    10222 + 0 + 710 + NCS + GETS                                                                 NA   MCI      NONE     NONE                                    10288 + 0 + 710 + NCS + GETS                                                                 NA   AT&T     NONE     NONE                                    10333 + 0 + 710 + NCS + GETS                                                                 NA   SPRINT   NONE     NONE                                    10XYZ + 0 + 710 + NCS + GETS                                                                 NA   BLOCK    NONE     NONE                                    10222 + 1 + 710 + NCS + GETS                                                                 MCI  MCI      HRR      NHRR                                    10288 + 1 + 710 + NCS + GETS                                                                 AT&T AT&T     HRR      NHRR                                    10333 + 1 + 710 + NCS + GETS                                                                 SPRINT                                                                             SPRINT   HRR      NHRR                                    10XYZ + 1 + 710 + NCS + GETS                                                                 NA   BLOCK    NONE     NONE                                    __________________________________________________________________________     Legend:                                                                       Other: CIC not equal to 288, 222 or 333 (CIC's of AT&T, MCI, or Sprint);      Block: Terminate call;                                                        NA: Not Applicable/Irrelevant; and                                            Office Default: Assigned by manager and stored in SCP 1008.              

The execution subroutine is shown in FIG. 5. At steps S132 and S134, theservice logic determines billing parameters and service measurements forpeg counts. Specifically, the system will assign values to ServiceFeature Codes and Peg Court values. These codes, as well as otherinformation associated with the call (e.g., call time, call date,originating number, originating city, originating state, call duration,call disposition, an IXC selection sequence, trunk group used, dialeddigits or destination number, etc.) are collected by a data distributorand sent to downstream information services for statistical analysis,billing or other reports. A list of preferred service codes and pegcounts are shown below in Tables 2 and 3, respectively.

                  TABLE 2                                                         ______________________________________                                        ACR Office Selection #                                                                     1      2       3    4    5     6                                 ______________________________________                                        Primary Carrier                                                                            288    288     222  222  333   333                               Alternate Carrier                                                                          222    333     288  333  288   222                               Secondary Carrier                                                                          333    222     333  288  222   288                               AIN 0.1 AMA Service                                                                        991    992     993  994  995   996                               Feature Code (Call Code                                                       840)                                                                          AIN 0.0 AMA Service                                                                        091    092     093  094  095   096                               Feature Code (Call Code                                                       843)                                                                          ______________________________________                                    

                  TABLE 3                                                         ______________________________________                                                                     Peg Count                                        Category  Result             Value                                            ______________________________________                                        1         Returned Selection Sequence is 1                                                                 01                                               2         Returned Selection Sequence is 2                                                                 02                                               3         Returned Selection Sequence is 3                                                                 03                                               4         Returned Selection Sequence is 4                                                                 04                                               5         Returned Selection Sequence is 5                                                                 05                                               6         Returned Selection Sequence is 6                                                                 06                                               7         Caller dialed invalid 10XYZ                                                                      07                                               8         Caller dialed 0+   08                                               9         Caller dialed 10288 + 0 (AT&T)                                                                   09                                               10        Caller dialed 10333 + 0 (Sprint)                                                                 10                                               11        Caller dialed 10222 + 0 (MCI)                                                                    11                                               ______________________________________                                    

Having logged the statistical information, SCP 1008 routes the abovedetermined information back to EO 1004 in the form of an SS7 queryresponse. EO 1004 then routes the dialed number at step S140 from EO1004 to the interexchange carrier corresponding to the primary carrier.If the EO 1004 cannot initiate a connection with that interexchangecarrier (e.g. the primary carrier or connecting lines experiences systemoverload, mechanical difficulties, or catastrophic failure) the systemroutes the dialed number through the interexchange carrier correspondingto the alternate carrier. If EO 1004 cannot connect with the alternatecarrier, then the it routes the call to the interexchange carriercorresponding to the secondary carrier.

The ability of the AIN network to perform all of the above steps, andthe type of information exchanged between EO 1004 and SCP 1008 dependson the type of trigger at the AIN EO. Specifically, for an AIN SSP 10digit trigger at AIN 0.1 SSP EO (using 5ESS and/or DMS switches), thenthe query message to SCP preferably contains the following information:

Crit₋₋ Type=NPANXXXXXX

Signaling Point Code of Office User Id=Calling Party DN

Called Party Id=7106274387

-NoN=National/Operator Req.

Calling Party Id=Calling Party TN

Primary Carrier=PIC of Line or 10XYZ-selected CIC

Carrier Selection=Was 10XYZ dialed?

For a typical response message to EO 1004, SCP 1008 preferably respondswith the following information:

Called Party Id=7106274387

-NoN=National/Operator Req.

Designation of Primary, Alternate, and Secondary Carriers

Calling Party Id=7106274387

AMASLPID=438700101

Overflow Billing Indicator

-Call code=840

-Service Feature Code (as assigned 990-996)

AMA Line Number=CPN of originating caller

For a DNT trigger at an AIN 0.0 SSP EO (using a 1AESS switch), theinformation preferably contained in the query message is as follows:

Service Key 710-627-4387

Signaling Point Code of Office

AIN=Calling Party AIN

-NoN=National

Carrier ID=PIC of Line or 10XYZ-selected CIC

Originating Station=CPN

SCP 1008 preferably sends the following information with the queryresponse message:

Routing Number=7106274387

-NoN=National

Designation of Primary, Alternate, and Secondary Carriers

Billing Indicator

-Call code=843

-Service Feature Code (as assigned 091-096)

Billing Number=AIN of originating line

As noted above, the above communication protocols are described for usewith the AIN system described herein. However, as the present inventionalso operates with non-AIN systems, AIN's having differentconfigurations, and software upgrades, protocols can be easily modifiedby those skilled in the art to accommodate such systems.

A feature of the present invention for use during the executionsubroutine is shown in FIG. 6, which can be used as an alternative tothe flowchart of FIG. 5. Steps S132, S134 and S140 are the same as thosediscussed above with reference to FIG. 5. Steps S136 and S138 relate toa feature of the invention to change the network calling party number(CPN) information from the value of the actual calling party to a GETSunique value (710-627-4387) for all GETS ACR calls. As shown in FIG. 6,the user is given the option to override the CPN at step S136. If thisoption is declined, control passes to step S140. If this option isaccepted, then CPN is changed to the dedicated number at step S138before control passes to step S140. The GETS unique CPN is passed alongwith other call information through the network to the interexchangecarrier. The AMA record will record the originating and terminatingnumber as the 710-NCS-GETS number. This feature can be activated by asimple toggle switch at the central control/SCP 1008.

The above description is dedicated to the use of a dedicated number overthe normal POTS trunk. However, pay phone call traffic (1+coin) isnormally sent over a specially translated trunk group. For certainswitches (presently the 5ESS and DMS-100), the GETS call may becompleted without the need for coins. Accordingly, in such aconfiguration, carriers AT&T, MCI, and Sprint send 1+coin calls to GETSover their normal POTS trunk group. The 710+NCS+GETS number is removedfrom the normal dialing plan, and treated as a domestic call so the callis routed along the normal route to the carrier rather than the coinroute. Other 710 type calls will use the coin route as appropriate.Further, since switches generally treat 1+coin calls as if AT&T is thePIC, AT&T will always be returned as the primary carrier, while thealternate and secondary carriers are selected from the remaining defaultsettings. However, it is within the skill in the art to set the primarycarrier to either MCI or Sprint for a particular pay phone.

A second embodiment of the service logic of the invention is shown inFIG. 7. In this service logic, entry 10XYZ requests a primary carrierwithout selection of alternate or secondary carriers, regardless ofwhether followed by 0 or 1. Thus, FIG. 7 is the same as FIG. 4, save forthe removal of steps S108, S110, and S112. The resultant permutations ofdialed numbers and assigned carriers, and the resulting peg counts, areshown below in Tables 4 and 5.

                                      TABLE 4                                     __________________________________________________________________________                                          SECONDARY                               CALLER DIALS   PIC is:                                                                            PRIMARY CXR                                                                            ALTERNATE CXR                                                                          ALTERNATE CXR                           __________________________________________________________________________    1 + 710 + NCS + GETS                                                                         AT&T AT&T     Highest Remaining                                                                      Next Highest                                                         Ranked (HRR)                                                                           Remaining Ranked                                                              (NHRR)                                  1 + 710 + NCS + GETS                                                                         MCI  MCI      HRR      NHRR                                    1 + 710 + NCS + GETS                                                                         SPRINT                                                                             SPRINT   HRR      NHRR                                    1 + 710 + NCS + GETS                                                                         OTHER                                                                              OFFICE DEFAULT                                                                         OFFICE DEFAULT                                                                         OFFICE DEFAULT                          0 + 710 + NCS + GETS                                                                         AT&T MCI      NONE     NONE                                    0 + 710 + NCS + GETS                                                                         MCI  MCI      NONE     NONE                                    0 + 710 + NCS + GETS                                                                         SPRINT                                                                             MCI      NONE     NONE                                    0 + 710 + NCS + GETS                                                                         OTHER                                                                              MCI      NONE     NONE                                    10222 + 0 + 710 + NCS + GETS                                                                 NA   MCI      NONE     NONE                                    10288 + 0 + 710 + NCS + GETS                                                                 NA   AT&T     NONE     NONE                                    10333 + 0 + 710 + NCS + GETS                                                                 NA   SPRINT   NONE     NONE                                    10XYZ + 0 + 710 + NCS + GETS                                                                 NA   BLOCK    NONE     NONE                                    10222 + 1 + 710 + NCS + GETS                                                                 NA   MCI      NONE     NONE                                    10288 + 1 + 710 + NCS + GETS                                                                 NA   AT&T     NONE     NONE                                    10333 + 1 + 710 + NCS + GETS                                                                 NA   SPRINT   NONE     NONE                                    10XYZ + 1 + 710 + NCS + GETS                                                                 NA   BLOCK    NONE     NONE                                    __________________________________________________________________________     Legend:                                                                       Other: CIC not equal to 288, 222 or 333 (CIC's of AT&T, MCI, or Sprint);      Block: Terminate call;                                                        NA: Not Applicable/Irrelevant; and                                            Office Default: Assigned by manager and stored in SCP 1008.              

                  TABLE 5                                                         ______________________________________                                                                     Peg Count                                        Category  Result             Value                                            ______________________________________                                        1         Returned Selection Sequence is 1                                                                 01                                               2         Returned Selection Sequence is 2                                                                 02                                               3         Returned Selection Sequence is 3                                                                 03                                               4         Returned Selection Sequence is 4                                                                 04                                               5         Returned Selection Sequence is 5                                                                 05                                               6         Returned Selection Sequence is 6                                                                 06                                               7         Caller dialed invalid 10XYZ                                                                      07                                               8         Caller dialed 0+   08                                               9         Caller dialed 10288 + 0/1 (AT&T)                                                                 09                                               10        Caller dialed 10333 + 0/1 (Sprint)                                                               10                                               11        Caller dialed 10222 + 0/1 (MCI)                                                                  11                                               ______________________________________                                    

The foregoing examples have been provided merely for the purpose ofexplanation and are in no way to be construed as limiting of the presentinvention. While the invention has been described with reference topreferred embodiments, it is understood that the words which have beenused herein are words of description and illustration, rather than wordsof limitations. Changes may be made without departing from the scope andspirit of the invention in its aspects. Although the invention has beendescribed herein with reference to particular means, materials andembodiments, the invention is not intended to be limited to theparticulars disclosed herein; rather, the invention extends to allfunctionally equivalent structures, methods and uses, such as are withinthe scope of the appended claims.

For example, although the use of three carriers (primary, alternate, andsecondary) is described specifically herein, the present invention isnot so limited to three carriers; and any number of multiple carriersmay be used. In addition, although the preferred carriers are MCI, AT&Tor Sprint, other carriers may be selected. Adjustments in the size ofthe table and/or the codes to utilize different carriers are well withinthe scope of one of ordinary skill in this art.

Similarly, the use of "288", "222", and "333" as the CIC's of thepreferred carriers, as well as other codes "10", "0" or "1", representcurrent industry norms. However, these values may be changed based onchanges in industry norms and/or the selection of different carriers.

Further, the present invention contemplates the use of the telephonenumber 710-NCS-GETS to reach the Government Emergency TelecommunicationsService. However, the invention is not so limited to this dedicatednumber and/or destination. Rather, the present invention can be used toroute any predetermined number to any desired location through therouting features discussed herein.

In yet another example, the present invention considers all defaultcarriers as authorized carrier, and vice versa. However, the inventionis not so limited, as other carriers besides those in the default listfor each location may be authorized carriers.

What is claimed:
 1. A method for routing a call based on a dialed numberfrom a location to one of a plurality of interexchange carriers, saidlocation having a predetermined sequence of ranked preferredinterexchange carriers assigned thereto, said methodcomprising:selecting one of a specific carrier and a default carrier;setting a primary carrier to said specific carrier when said specificcarrier is selected, and to one of an authorized Primary InterexchangeCarrier and a first ranked carrier of said predetermined sequence ofranked preferred interexchange carriers for said location when saiddefault carrier is selected; selecting at least one alternate carriersequentially from a highest remaining ranked carrier in saidpredetermined sequence of ranked preferred carriers; and sequentiallyrouting said call to said primary carrier and said at least onealternate carrier until a connection is established.
 2. The method ofclaim 1, wherein said primary carrier is set to said first rankedcarrier when said default carrier is requested and said PrimaryInterexchange Carrier is not an authorized carrier.
 3. The method ofclaim 1, further comprising providing at least one of a service code anda peg count code based upon at least one of said dialed number, saidpredetermined sequence of ranked preferred interexchange carriers, and asequence formed by said primary carrier and said at least one alternatecarrier.
 4. The method of claim 3, further comprising recording said atleast one of said service code and said peg count code for laterretrieval and statistical analysis.
 5. The method of claim 4, whereinsaid recording includes recording data regarding said dialed number,said data including at least one of call time, call date, originatingnumber, originating city, originating state, call duration, calldisposition, interexchange carrier, interechange selection sequence,trunk group used, dialed digits and destination number.
 6. The method ofclaim 3, further comprising recording said codes for later retrieval andbilling.
 7. The method of claim 1, wherein said location has a callingparty number, said method further comprising selectively overriding saidcalling number with a dedicated number.
 8. The method of claim 1,wherein said selecting and sequentially routing are not performed ifsaid specific carrier is not an authorized carrier.
 9. The method ofclaim 1, wherein said selecting includes entering a prefix code withsaid dialed number.
 10. The method of claim 8, furthercomprising:storing said predetermined sequence of ranked preferredcarriers in a look up table; and said selecting includes consulting saidlook up table to locate said highest and next highest remaining rankedcarrier.
 11. A method for routing a government emergency call from oneof a plurality of locations through one of a plurality of carriers, eachof said plurality of locations having predetermined ranking of preferredinterexchange carriers, assigned thereto comprising:recognizing saidcall at one location of said plurality of locations; setting a primarycarrier, in order of preference, to one of an authorized manuallyselected carrier if entered, an authorized Primary InterexchangeCarrier, and a first ranked carrier of said predetermined ranking ofpreferred carriers for said one location; selecting an alternate andsecondary carrier sequentially from a highest and next highest remainingcarrier in said predetermined ranking of preferred carriers for said onelocation, respectively; and sequentially routing said call tointerexchange carriers corresponding to said primary carrier, and tosaid alternate and secondary carriers when selected, until a connectionis established.
 12. The method of claim 11, further comprisingdisconnecting a user if a code for an unauthorized interexchange carrieris requested by a user when dialing said call.
 13. The method of claim11, wherein each predetermined ranking of preferred carriers for each ofsaid plurality of locations includes, in order of preference, said firstcarrier, and second and third carriers, wherein if a user does notmanually select a carrier and said Primary Interexchange Carrier isunauthorized, then said primary, alternate and secondary carriers areset to said first, second and third carriers for said one location. 14.The method of claim 11, wherein each predetermined ranking of preferredinterexchange carriers for said plurality of locations includes threecarriers.
 15. The method of claim 11, further comprising recording dataassociated with said call, including at least one of a call time, a calldate, an originating number, an originating city, an originating state,a call duration, a call disposition, an interexchange carrier, aninterexchange selection sequence, a trunk group used, dialed digits, anda destination number.
 16. A network capable of routing a call based on adialed dedicated number through a plurality of interexchange carriersupon entry of said dedicated number and a request code, said networkincluding a device for dialing said dedicated number and said requestcode, a node connected to said device, and a central control connectedto said node, said node having a predetermined sequence of threepreferred carriers, assigned thereto comprising:said node requestingcarrier data from said central control responsive to entry of saiddedicated number; said central control, responsive to a first conditionof said request code, setting a primary carrier to one of said threepreferred carriers which has a carrier identification code that matchesa predetermined portion of said request code; said central control,responsive to a second condition of said request code, disconnectingsaid call; said central control, responsive to a third condition of saidrequest code, setting a primary carrier to a Primary InterexchangeCarrier for said node if said Primary Interexchange Carrier isauthorized, and to a first ranked carrier of said three preferredcarriers if said Primary Interexchange Carrier is not authorized; saidcentral control, responsive to a fourth condition of said request code,setting an alternate carrier to a highest remaining rank carrier of saidthree preferred carriers, and setting a secondary carrier to a nexthighest remaining rank carriers of said three preferred carriers; saidcentral control replying to said node with said carrier data, includingat least said primary carrier, and said alternate and secondary carrierswhen set; said node routing said call to an interexchange carriercorresponding to said primary carrier; and said node, responsive to aselection of alternate and secondary carriers by said central controland a failure of said node to connect with said interexchange carriercorresponding to said primary carrier, sequentially routing said call toan interexchange carrier corresponding to said alternate and secondarycarriers until a connection established.
 17. The network of claim 16,wherein said network is an Advanced Intelligent Network, said node is anend office, and said central control is a service control point.
 18. Thenetwork of claim 16, wherein said first condition is entry of a codewhich request a specific authorized carrier, said second condition isentry of a code which does not correspond to an authorized carrier, saidthird condition is entry of a code which does not request a specificcarrier, and said fourth condition is entry of a code which requestsassignment of alternate and secondary carriers.
 19. The network of claim16, said central control further providing classification data based onat least one of said requested code and said carrier data, wherein saidclassification data may be retrieved for at least one of statisticalanalysis and billing.
 20. The network of claim 16, wherein saiddedicated number is entered at a location having a calling party number,said system further comprising means for selectively changing saidcalling party number to match said dedicated number.
 21. A system forimproving the probability that a call based on a dialed dedicated numberwill be routed through a node to one of a plurality of interexchangecarriers, said node having a predetermined sequence of preferredcarriers assigned thereto, comprising:means for recognizing saiddedicated number; means for assigning primary, alternate and secondaryinterexchange carriers responsive to said means for recognizing; andmeans for sequentially routing said dedicated number from said node tosaid primary, alternate, and secondary carriers until a connection isestablished.
 22. The system of claim 21, further comprising means forassigning classification data based on at least one of a code input withsaid dedicated number and the assigned primary, alternate, and secondarycarriers, said classification data being used for at least one ofstatistical analysis and billing.
 23. The system of claim 21, furthercomprising an advanced intelligent network, said node is an end officeof said network, and said dedicated number is entered at a deviceconnected to said end office.
 24. A method for routing a call based on adialed number from a location to one of a plurality of interexchangecarriers, said location having a predetermined sequence of rankedpreferred interexchange carriers, assigned thereto said methodcomprising:setting a primary carrier to one of an authorized PrimaryInterexchange Carrier and a first ranked carrier of said predeterminedsequence of ranked preferred carriers for said location; selecting atleast one alternate carrier sequentially from a highest remaining rankedcarrier in said predetermined sequence of ranked preferred carriers; andsequentially routing said call to said primary carrier and said at leastone alternate carrier until a connection is established.
 25. The methodof claim 24, wherein said primary carrier is set to said first rankedcarrier when said Primary Interexchange Carrier is not an authorizedcarrier.
 26. The method of claim 24, further comprising providing atleast one of a service code and a peg count code based upon at least oneof said dialed number, said predetermined sequence of ranked preferredinterexchange carriers, and a sequence formed by said primary carrierand said at least one alternate carrier.
 27. The method of claim 26,further comprising recording said at least one of said service code andsaid peg count code for later retrieval and statistical analysis. 28.The method of claim 26, wherein said recording includes recording dataregarding said dialed number, said data including at least one of calltime, call date, originating number, originating city, originatingstate, call duration, call disposition, an interexchange carrier, aninterexchange carrier selection sequence, trunk group used, dialeddigits and destination number.
 29. The method of claim 26, furthercomprising recording said codes for later retrieval and billing.
 30. Themethod of claim 24, wherein said location has a calling party number,said method further comprising selectively overriding said calling partynumber with a dedicated number.
 31. The method of claim 24, furthercomprising:storing said predetermined sequence of ranked preferredcarriers in a look up table; and said selecting includes consulting saidlook up table to locate said highest remaining ranked carrier.
 32. Amethod for routing a call from one of a plurality of locations throughone of a plurality of carriers, each of said plurality of locationshaving a predetermined ranking of preferred interexchange carriers,assigned thereto comprising:recognizing said call at one location ofsaid plurality of locations; setting a primary carrier, in order ofpreference, to one of an authorized manually selected carrier ifentered, an authorized Primary Interexchange Carrier, and a first rankedcarrier of said predetermined ranking of preferred carriers for said onelocation; selecting, when said authorized manually selected carrier isnot entered, an alternate and secondary carrier sequentially from ahighest and next highest remaining carrier in said predetermined rankingof preferred carriers for said one location, respectively; andsequentially routing said call to interexchange carriers correspondingto said primary carrier, and said alternate, and secondary carriers whenselected, until a connection is established.
 33. The method of claim 32,further comprising disconnecting a user if a code for an unauthorizedinterexchange carrier is requested by a user when dialing said call. 34.The method of claim 32, wherein each predetermined ranking of preferredcarriers for each of said plurality of locations includes, in order ofpreference, said first carrier, and second and third carriers, whereinif a user does not manually select a carrier and said PrimaryInterexchange Carrier is unauthorized, then said primary, alternate andsecondary carriers are set to said first, second and third carriers forsaid one location.
 35. The method of claim 32, wherein eachpredetermined ranking of preferred carriers for said plurality oflocations includes three interexchange carriers.
 36. The method of claim32, further comprising recording data associated with said call,including at least one of a call time, a call date, an originatingnumber, an originating city, an originating state, a call duration, acall disposition, an interexchange carrier, an interexchange carrierselection sequence, a trunk group used, dialed digits, and a destinationnumber.
 37. A network capable of routing a call based on a dial anddedicated number through a plurality of interexchange carriers uponentry of said dedicated number and a request code, said networkincluding a device for dialing said dedicated number and said requestcode, a node connected to said device, and a central control connectedto said node, said node having a predetermined sequence of preferredcarriers, assigned thereto comprising:said node requesting carrier datafrom said central control responsive to entry of said dedicated number;said central control, responsive to a first condition of said requestcode, setting a primary carrier to one of said predetermined sequence ofpreferred carriers which has a carrier identification code that matchesa predetermined portion of said request code; said central control,responsive to a second condition of said request code, disconnectingsaid call; said central control, responsive to a third condition of saidrequest code, setting said primary carrier to a Primary InterexchangeCarrier for said node if said Primary Interexchange Carrier isauthorized, and to a first ranked carrier of said predetermined sequenceof preferred carriers if said Primary Interexchange Carrier is notauthorized; said central control, responsive to said third condition ofsaid request code, setting an alternate carrier to a highest remainingrank carrier of said predetermined sequence of preferred carriers, andsetting a secondary carrier to a next highest remaining rank carriers ofsaid preferred carriers; said central control replying to said node withsaid carrier data, including at least said primary carrier, and saidalternate and secondary carriers when set; said node routing said callto an interexchange carrier corresponding to said primary carrier; andsaid node, responsive to a selection of alternate and secondary carriersby said central control and a failure of said node to connect with saidinterexchange carrier corresponding to said primary carrier,sequentially routing said call to an interexchange carrier correspondingto said alternate and secondary carriers until a connection established.38. The network of claim 37, wherein said network is an AdvancedIntelligent Network, said node is an end office, and said centralcontrol is a service control point.
 39. The network of claim 37, whereinsaid first condition is entry of a code which requests a specificauthorized carrier, said second condition is entry of a code which doesnot correspond to an authorized interexchange carrier, and said thirdcondition is entry of a code which does not request a specific carrier.40. The network of claim 37, said central control further providingclassification data based on at least one of said requested code andsaid carrier data, wherein said classification data may be retrieved forat least one of statistical analysis and billing.
 41. The network ofclaim 37, wherein said dedicated number is entered at a location havinga calling party number, said system further comprising means forselectively changing said calling party number to match said dedicatednumber.